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Journal ArticleDOI

High-resolution electroluminescent imaging of pressure distribution using a piezoelectric nanowire LED array

01 Sep 2013-Nature Photonics (Nature Research)-Vol. 7, Iss: 9, pp 752-758
TL;DR: An array of piezoelectric nanowire LEDs with a pixel density of 6,350 dpi is capable of mapping two-dimensional pressure distributions with a spatial resolution of 2.7 micrometres as mentioned in this paper.
Abstract: An array of piezoelectric nanowire LEDs with a pixel density of 6,350 dpi is capable of mapping two-dimensional pressure distributions with a spatial resolution of 2.7 micrometres. Pressure alters the light emissions from the LEDs, which are then imaged. Possible applications include artificial skin, robotics and touchpads.
Citations
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Journal ArticleDOI
04 Apr 2014-Science
TL;DR: Experimental and theoretical approaches for using ideas in soft microfluidics, structured adhesive surfaces, and controlled mechanical buckling to achieve ultralow modulus, highly stretchable systems that incorporate assemblies of high-modulus, rigid, state-of-the-art functional elements are described.
Abstract: When mounted on the skin, modern sensors, circuits, radios, and power supply systems have the potential to provide clinical-quality health monitoring capabilities for continuous use, beyond the confines of traditional hospital or laboratory facilities. The most well-developed component technologies are, however, broadly available only in hard, planar formats. As a result, existing options in system design are unable to effectively accommodate integration with the soft, textured, curvilinear, and time-dynamic surfaces of the skin. Here, we describe experimental and theoretical approaches for using ideas in soft microfluidics, structured adhesive surfaces, and controlled mechanical buckling to achieve ultralow modulus, highly stretchable systems that incorporate assemblies of high-modulus, rigid, state-of-the-art functional elements. The outcome is a thin, conformable device technology that can softly laminate onto the surface of the skin to enable advanced, multifunctional operation for physiological monitoring in a wireless mode.

975 citations


Cites background from "High-resolution electroluminescent ..."

  • ...Recent work demonstrates that such characteristics can be achieved by exploiting ultrathin geometries (1, 6, 7), soft active materials (3, 4, 8–13), and/or liquid metals (14–16)....

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Journal ArticleDOI
TL;DR: A detailed explanation of the unique properties associated with the one-dimensional nanowire geometry will be presented, and the benefits of these properties for the various applications will be highlighted.
Abstract: Semiconductor nanowires (NWs) have been studied extensively for over two decades for their novel electronic, photonic, thermal, electrochemical and mechanical properties. This comprehensive review article summarizes major advances in the synthesis, characterization, and application of these materials in the past decade. Developments in the understanding of the fundamental principles of "bottom-up" growth mechanisms are presented, with an emphasis on rational control of the morphology, stoichiometry, and crystal structure of the materials. This is followed by a discussion of the application of nanowires in i) electronic, ii) sensor, iii) photonic, iv) thermoelectric, v) photovoltaic, vi) photoelectrochemical, vii) battery, viii) mechanical, and ix) biological applications. Throughout the discussion, a detailed explanation of the unique properties associated with the one-dimensional nanowire geometry will be presented, and the benefits of these properties for the various applications will be highlighted. The review concludes with a brief perspective on future research directions, and remaining barriers which must be overcome for the successful commercial application of these technologies.

789 citations

Journal ArticleDOI
01 Jul 2017-Small
TL;DR: This Review summarizes the recent progress of flexible sensing electronics for their use in wearable/attachable health monitoring systems, and presents an overview of different materials and configurations for flexible sensors, including piezo-resistive, piezos-electrical, capacitive, and field effect transistor based devices.
Abstract: Wearable or attachable health monitoring smart systems are considered to be the next generation of personal portable devices for remote medicine practices. Smart flexible sensing electronics are components crucial in endowing health monitoring systems with the capability of real-time tracking of physiological signals. These signals are closely associated with body conditions, such as heart rate, wrist pulse, body temperature, blood/intraocular pressure and blood/sweat bio-information. Monitoring such physiological signals provides a convenient and non-invasive way for disease diagnoses and health assessments. This Review summarizes the recent progress of flexible sensing electronics for their use in wearable/attachable health monitoring systems. Meanwhile, we present an overview of different materials and configurations for flexible sensors, including piezo-resistive, piezo-electrical, capacitive, and field effect transistor based devices, and analyze the working principles in monitoring physiological signals. In addition, the future perspectives of wearable healthcare systems and the technical demands on their commercialization are briefly discussed.

708 citations

Journal ArticleDOI
TL;DR: To imitate tactile sensing via e‐skins, flexible and stretchable pressure sensor arrays are constructed based on different transduction mechanisms and structural designs that can map pressure with high resolution and rapid response beyond that of human perception.
Abstract: The skin is the largest organ of the human body and can sense pressure, temperature, and other complex environmental stimuli or conditions. The mimicry of human skin's sensory ability via electronics is a topic of innovative research that could find broad applications in robotics, artificial intelligence, and human-machine interfaces, all of which promote the development of electronic skin (e-skin). To imitate tactile sensing via e-skins, flexible and stretchable pressure sensor arrays are constructed based on different transduction mechanisms and structural designs. These arrays can map pressure with high resolution and rapid response beyond that of human perception. Multi-modal force sensing, temperature, and humidity detection, as well as self-healing abilities are also exploited for multi-functional e-skins. Other recent progress in this field includes the integration with high-density flexible circuits for signal processing, the combination with wireless technology for convenient sensing and energy/data transfer, and the development of self-powered e-skins. Future opportunities lie in the fabrication of highly intelligent e-skins that can sense and respond to variations in the external environment. The rapidly increasing innovations in this area will be important to the scientific community and to the future of human life.

679 citations

Journal ArticleDOI
TL;DR: In this paper, the authors predict anisotropic piezoelectric effects in intrinsic monolayer group IV monochalcogenides (MX, M=Sn or Ge, X=Se or S), including SnSe, SnS, GeSe, and GeS.
Abstract: We predict enormous, anisotropic piezoelectric effects in intrinsic monolayer group IV monochalcogenides (MX, M=Sn or Ge, X=Se or S), including SnSe, SnS, GeSe, and GeS. Using first-principle simulations based on the modern theory of polarization, we find that their piezoelectric coefficients are about one to two orders of magnitude larger than those of other 2D materials, such as MoS2 and GaSe, and bulk quartz and AlN which are widely used in industry. This enhancement is a result of the unique “puckered” C2v symmetry and electronic structure of monolayer group IV monochalcogenides. Given the achieved experimental advances in the fabrication of monolayers, their flexible character, and ability to withstand enormous strain, these 2D structures with giant piezoelectric effects may be promising for a broad range of applications such as nano-sized sensors, piezotronics, and energy harvesting in portable electronic devices.

571 citations

References
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Journal ArticleDOI
14 Apr 2006-Science
TL;DR: This approach has the potential of converting mechanical, vibrational, and/or hydraulic energy into electricity for powering nanodevices.
Abstract: We have converted nanoscale mechanical energy into electrical energy by means of piezoelectric zinc oxide nanowire (NW) arrays. The aligned NWs are deflected with a conductive atomic force microscope tip in contact mode. The coupling of piezoelectric and semiconducting properties in zinc oxide creates a strain field and charge separation across the NW as a result of its bending. The rectifying characteristic of the Schottky barrier formed between the metal tip and the NW leads to electrical current generation. The efficiency of the NW-based piezoelectric power generator is estimated to be 17 to 30%. This approach has the potential of converting mechanical, vibrational, and/or hydraulic energy into electricity for powering nanodevices.

6,692 citations

Journal ArticleDOI
TL;DR: Transparent, conducting spray-deposited films of single-walled carbon nanotubes are reported that can be rendered stretchable by applying strain along each axis, and then releasing this strain.
Abstract: Transparent films of carbon nanotubes can accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm−1 in the stretched state.

2,847 citations

Journal ArticleDOI
TL;DR: Flexible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin films of the biocompatible elastomer polydimethylsiloxane are demonstrated.
Abstract: The development of an electronic skin is critical to the realization of artificial intelligence that comes into direct contact with humans, and to biomedical applications such as prosthetic skin. To mimic the tactile sensing properties of natural skin, large arrays of pixel pressure sensors on a flexible and stretchable substrate are required. We demonstrate flexible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin films of the biocompatible elastomer polydimethylsiloxane. The pressure sensitivity of the microstructured films far surpassed that exhibited by unstructured elastomeric films of similar thickness, and is tunable by using different microstructures. The microstructured films were integrated into organic field-effect transistors as the dielectric layer, forming a new type of active sensor device with similarly excellent sensitivity and response times.

2,627 citations

Journal ArticleDOI
TL;DR: Integration of organic transistors and rubber pressure sensors, both of which can be produced by low-cost processing technology such as large-area printing technology, will provide an ideal solution to realize a practical artificial skin.
Abstract: It is now widely accepted that skin sensitivity will be very important for future robots used by humans in daily life for housekeeping and entertainment purposes Despite this fact, relatively little progress has been made in the field of pressure recognition compared to the areas of sight and voice recognition, mainly because good artificial “electronic skin” with a large area and mechanical flexibility is not yet available The fabrication of a sensitive skin consisting of thousands of pressure sensors would require a flexible switching matrix that cannot be realized with present silicon-based electronics Organic field-effect transistors can substitute for such conventional electronics because organic circuits are inherently flexible and potentially ultralow in cost even for a large area Thus, integration of organic transistors and rubber pressure sensors, both of which can be produced by low-cost processing technology such as large-area printing technology, will provide an ideal solution to realize a practical artificial skin, whose feasibility has been demonstrated in this paper Pressure images have been taken by flexible active matrix drivers with organic transistors whose mobility reaches as high as 14 cm2/V·s The device is electrically functional even when it is wrapped around a cylindrical bar with a 2-mm radius

1,804 citations

Journal ArticleDOI
TL;DR: This work presents the largest integration of ordered NW-array active components, and demonstrates a model platform for future integration of nanomaterials for practical applications.
Abstract: Large-scale integration of high-performance electronic components on mechanically flexible substrates may enable new applications in electronics, sensing and energy. Over the past several years, tremendous progress in the printing and transfer of single-crystalline, inorganic micro- and nanostructures on plastic substrates has been achieved through various process schemes. For instance, contact printing of parallel arrays of semiconductor nanowires (NWs) has been explored as a versatile route to enable fabrication of high-performance, bendable transistors and sensors. However, truly macroscale integration of ordered NW circuitry has not yet been demonstrated, with the largest-scale active systems being of the order of 1 cm(2) (refs 11,15). This limitation is in part due to assembly- and processing-related obstacles, although larger-scale integration has been demonstrated for randomly oriented NWs (ref. 16). Driven by this challenge, here we demonstrate macroscale (7×7 cm(2)) integration of parallel NW arrays as the active-matrix backplane of a flexible pressure-sensor array (18×19 pixels). The integrated sensor array effectively functions as an artificial electronic skin, capable of monitoring applied pressure profiles with high spatial resolution. The active-matrix circuitry operates at a low operating voltage of less than 5 V and exhibits superb mechanical robustness and reliability, without performance degradation on bending to small radii of curvature (2.5 mm) for over 2,000 bending cycles. This work presents the largest integration of ordered NW-array active components, and demonstrates a model platform for future integration of nanomaterials for practical applications.

1,188 citations